NEW YORK — Swedish teen climate activist Greta Thunberg arrived in New York City to chants and cheers Wednesday after a trans-Atlantic trip on a sailboat to attend a global warming conference.

Thunberg, 16, and her crew were escorted into a lower Manhattan marina at about 4 p.m., concluding a two-week crossing from Plymouth, England. Hundreds of activists gathered on a Hudson River promenade to cheer her arrival.

Thunberg waved, was lifted onto a dock, then took her first wobbly steps on dry land.

“All of this is very overwhelming,” she said of the reception, looking slightly embarrassed.

The teenager refused to fly because of the carbon cost of plane travel. A 2018 study said that because of cloud and ozone formation, air travel may trap two to four times more heat than that caused by just emissions of carbon dioxide and other greenhouse gases.

Speaking to reporters after she landed, Thunberg said the trip wasn’t as uncomfortable as she expected. She didn’t get seasick once, she said. But she stressed that “this is not something I want everyone to do.”

“It is insane that a 16-year-old would have to cross the Atlantic Ocean to make a stand,” she said. “The climate and ecological crisis is a global crisis, the biggest crisis that humanity has ever faced, and if we don’t manage to work together and to cooperate and to work together despite our differences, then we will fail.”

Thunberg has become a symbol of a growing movement of young climate activists, leading weekly school strikes in Sweden that inspired similar actions in about 100 cities.

She’s in New York to speak at the United Nations Climate Action Summit next month. There, she’ll join world leaders who will present plans to reduce greenhouse gas emissions.

The boat carrying Thunberg, the Malizia II, encountered rough seas that slowed it down for a day. Taking turns steering the 60-foot (18-meter) racing yacht were two skippers Boris Herrmann and Pierre Casiraghi, the grandson of Monaco’s late Prince Rainier III and American actress Grace Kelly.

This was no pleasure cruise. The Malizia is built for high-speed, offshore racing, and weight is kept to a minimum. There is no toilet — just a bucket — or fixed shower aboard, no windows below deck and only a small gas cooker to heat up freeze-dried food.

The sailboat’s onboard electronics are powered by solar panels and underwater turbines.

Thunberg, the daughter of an actor and an opera singer, became a European celebrity last year when she refused to go to school in the weeks before Sweden’s general election to highlight the impact of climate change.

She continued her school strike on Fridays after the election, spurring thousands of young people to follow suit. Since then, she’s met the pope, spoken at Davos and attended anti-coal protests in Germany.

She is now taking a year off school to pursue her activism.

Her father, Svante Thunberg, crossed the ocean with her.

“He had to, because I had made up my mind I was going to go and he has to take care of me,” she told The Associated Press, standing on a swaying dock by the sailboat. “He didn’t want to, but I sort of forced him to do it and I think he’s happy he did it.”

The most dramatic moments came “when you’re doing like 27, 28 knots and it’s very, very bumpy and you just try to hold on and not fall,” she said.

The boat was accompanied into New York by a flotilla of 17 sailboats the United Nations organized — one for each of the 17 U.N. goals to end poverty and preserve the environment by 2030, including action to prevent climate change.

Greta Thunberg, a 16-year-old Swedish climate activist, sails into New York harbor aboard the Malizia II, Wednesday, Aug. 28, 2019. The zero-emissions yacht left Plymouth, England on Aug. 14. She is scheduled to address the United Nations Climate Action Summit on Sept. 23. (AP Photo/Bebeto Matthews)

Upon her arrival in New York, Thunberg was asked whether she had a message for U.S. President Donald Trump, who rejects mainstream climate science.

“My message for him is just: listen to the science,” she said. “And he obviously doesn’t do that. So as I always say to this question: If no one has been able to convince him about the climate crisis, the urgency, then why should I be able to do that? So I am just going to focus on spreading awareness.”

But far simpler things took precedence in her first hours in Manhattan. She said she can finally rest, take a shower and enjoy meals of “fresh vegetables, not freeze-dried food” like canned beans and corn.

By VERENA DOBNIK Associated Press

Associated Press Science Writer Seth Borenstein in Washington contributed to this report.

Greta Thunberg, a 16-year-old Swedish climate activist, sails into New York harbor aboard the Malizia II, Wednesday, Aug. 28, 2019. The zero-emissions yacht left Plymouth, England on Aug. 14. She is scheduled to address the United Nations Climate Action Summit on Sept. 23. (AP Photo/Mary Altaffer)

Greta Thunberg, a 16-year-old Swedish climate activist, sails into New York harbor aboard the Malizia II, Wednesday, Aug. 28, 2019. The zero-emissions yacht left Plymouth, England on Aug. 14. She is scheduled to address the United Nations Climate Action Summit on Sept. 23. (AP Photo/Mary Altaffer)